libbacktrace: support returning discriminator field

Based on patch from Andi Kleen.

	* backtrace.h (backtrace_create_state): Rewrite comment to change
	threaded parameter to flags.
	(backtrace_full_callback, backtrace_syminfo_callback): Document
	behavior change if moredata flag is set.
	(struct backtrace_moredata): Define.
	* backtrace-supported.h.in (BACKTRACE_SUPPORTS_MOREDATA): Define.
	* internal.h (struct backtrace_state): Add moredata field.
	(BACKTRACE_MOREDATA_VERSION): Define.
	* state.c (backtrace_create_state): Change threaded parameter to
	flags.  Set state moredata field based on flags.
	* dwarf.c (struct line): Add disc field.
	(struct function): Add caller_disc field.
	(call_callback): New static function.
	(add_line): Add disc parameter.  Change all callers.  Store disc
	in new line value.
	(read_line_program): Track discriminator value.
	(read_line_info): Initialize disc field in final line entry.
	(read_function_entry): Handle DW_AT_GNU_discriminator.
	(report_inlined_functions): Add disc parameter. Change all
	callers. Call call_callback rather than calling callback
	directly.
	(dwarf_lookup_pc): Handle inlined discriminators. Call
	call_callback rather than calling callback directly.
	(dwarf_fileline): Call call_callback rather than calling callback
	directly.
	* elf.c (elf_syminfo): Pass moredata if requested.
	* macho.c (macho_syminfo): Likewise.
	* pecoff.c (coff_syminfo): Likewise.
	* xcoff.c (xcoff_syminfo): Likewise.
	(xcoff_lookup_pc): Likewise.
	* backtrace.c: #include <string.h>.
	(unwind): Pass moredata if requested.
	* unknown.c: #include <string.h>.
	(unknown_fileline): Pass moredata if requested.
	* fileline.c (backtrace_syminfo_to_full_callback): Add comment
	about moredata.
	* mdtest.c: New test file.
	* Makefile.am (mdtest_SOURCES): Define.
	(mdtest_CFLAGS, mdtest_LDFLAGS, mdtest_LDADD): Define.
	(BUILDTESTS): Add mdtest.
	* Makefile.in: Regenerate.

xcoff.c

@@ -512,6 +512,8 @@ xcoff_syminfo (struct backtrace_state *state ATTRIBUTE_UNUSED, uintptr_t addr,
   struct xcoff_syminfo_data *edata;
   struct xcoff_symbol *sym = NULL;
   const char *name;
+  void *mdata;
+  struct backtrace_moredata md;
 
   if (!state->threaded)
     {
@@ -547,15 +549,25 @@ xcoff_syminfo (struct backtrace_state *state ATTRIBUTE_UNUSED, uintptr_t addr,
 	}
     }
 
+  if (!state->moredata)
+    mdata = data;
+  else
+    {
+      memset (&md, 0, sizeof md);
+      md.backtrace_version = 3;
+      md.backtrace_data = data;
+      mdata = (void *) &md;
+    }
+
   if (sym == NULL)
-    callback (data, addr, NULL, 0, 0);
+    callback (mdata, addr, NULL, 0, 0);
   else
     {
       name = sym->name;
       /* AIX prepends a '.' to function entry points, remove it.  */
       if (name && *name == '.')
 	++name;
-      callback (data, addr, name, sym->address, sym->size);
+      callback (mdata, addr, name, sym->address, sym->size);
     }
 }
 
@@ -723,7 +735,7 @@ xcoff_incl_search (const void *vkey, const void *ventry)
    0 if not.  */
 
 static int
-xcoff_lookup_pc (struct backtrace_state *state ATTRIBUTE_UNUSED,
+xcoff_lookup_pc (struct backtrace_state *state,
 		 struct xcoff_fileline_data *fdata, uintptr_t pc,
 		 backtrace_full_callback callback,
 		 backtrace_error_callback error_callback ATTRIBUTE_UNUSED,
@@ -805,7 +817,18 @@ xcoff_lookup_pc (struct backtrace_state *state ATTRIBUTE_UNUSED,
   /* AIX prepends a '.' to function entry points, remove it.  */
   if (function != NULL && *function == '.')
     ++function;
-  return callback (data, pc, filename, lnno, function);
+
+  if (!state->moredata)
+    return callback (data, pc, filename, lnno, function);
+  else
+    {
+      struct backtrace_moredata md;
+
+      memset (&md, 0, sizeof md);
+      md.backtrace_version = 3;
+      md.backtrace_data = data;
+      return callback ((void *) &md, pc, filename, lnno, function);
+    }
 }
 
 /* Return the file/line information for a PC using the XCOFF lineno
@@ -855,7 +878,17 @@ xcoff_fileline (struct backtrace_state *state, uintptr_t pc,
 
   /* FIXME: See if any libraries have been dlopen'ed.  */
 
-  return callback (data, pc, NULL, 0, NULL);
+  if (!state->moredata)
+    return callback (data, pc, NULL, 0, NULL);
+  else
+    {
+      struct backtrace_moredata md;
+
+      memset (&md, 0, sizeof md);
+      md.backtrace_version = 3;
+      md.backtrace_data = data;
+      return callback ((void *) data, pc, NULL, 0, NULL);
+    }
 }
 
 /* Initialize the function vector info for xcoff_fileline.  */